1. Field of the Invention
This invention relates generally to damascene methods of manufacturing write coils or other suitable components of magnetic heads.
2. Description of the Related Art
Computers often include auxiliary memory storage devices having media on which data can be written and from which data can be read for later use. A direct access storage device (e.g. a disk drive) incorporating rotating magnetic disks is commonly used for storing data in magnetic form on the disk surfaces. Data is recorded on concentric, radially spaced tracks on the disk surfaces with magnetic heads. A write coil of the magnetic head is utilized to facilitate such data-writing. Read sensors in the magnetic heads are then used to read data from the tracks on the disk surfaces.
Damascene methods have been used in the manufacture of write coils of magnetic heads. One conventional damascene method involves the steps of forming a hard mask layer of SiO2 over an insulator material such as hard-baked resist; forming a photoresist layer over the hard mask layer; performing an image patterning process to produce a write coil pattern in the photoresist layer; performing a first etching process (namely a plasma etch or reactive ion etch (RIE) using a gas such as CH4) to remove portions of the hard mask layer in accordance with the write coil pattern; performing a second etching process (namely a plasma etch or RIE using gases such as N2H2 and C2H4) to remove portions of the hard-baked resist in accordance with the write coil pattern; depositing one or more seed layers which include tantalum (Ta) over the structure; electroplating copper (Cu) within the etched portion of the hard-baked resist; performing a first chemical-mechanical polishing (CMP) process over the structure using a first slurry to remove the top remaining Cu material; and performing a second CMP process over the structure using a second slurry to remove the top remaining hard mask material.
Some problems exist with the above-described method. For one, remaining hard mask material left over top of the structure before the CMP adversely affects the quality of the CMP, during which undesirable mask fragments are produced. Also, remaining hard mask material tends to produce an undercut which affects the step-coverage of the tantalum seed layer. Furthermore, the use of two different slurries may be required for the CMP.
Other problems relate particularly to the use of SiO2 as the hard mask material when hard-baked resist is used as the insulator material. For one, the selectivity of the SiO2 is relatively low (SiO2 to hard-baked resist may be about 30:1) and undesirably requires the deposition of a relatively thick layer (e.g. 4000 Å of SiO2). Furthermore, SiO2 does not adhere well to hard-baked resist and therefore an adhesion promoter such as hexamethyldisilazane (HMDS) is needed, which is a relatively expensive step. Finally, the stress of the SiO2 layer and its brittleness also become issues.
Accordingly, what are needed are improved damascene methods for forming write coils of magnetic heads.